Why D const is annoying

[Jonathan M Davis]

On Wednesday, May 02, 2012 11:58:41 Mehrdad wrote:
> Er, I guess I didn't say what I actually meant to say, my bad. x_x
> 
> What I meant that you're assuming that derived classes won't need mutable
> state in an const method that they overrode.

If a const function needs mutable member variables or non-const member 
functions, then it cannot exist. And so if a derived class requires that, then 
it cannot exist. Putting const on a member function puts certain requirements 
on it (the same goes for nothrow, pure, and @safe), and any derived class must 
meet those requirements with its overridden version. It's part of the function's
signature just like the return type is.

- Jonathan M Davis